CA1164065A - Automatic shunt device - Google Patents
Automatic shunt deviceInfo
- Publication number
- CA1164065A CA1164065A CA000363711A CA363711A CA1164065A CA 1164065 A CA1164065 A CA 1164065A CA 000363711 A CA000363711 A CA 000363711A CA 363711 A CA363711 A CA 363711A CA 1164065 A CA1164065 A CA 1164065A
- Authority
- CA
- Canada
- Prior art keywords
- data
- terminals
- output data
- output
- terminal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 230000000007 visual effect Effects 0.000 claims description 5
- 230000003213 activating effect Effects 0.000 claims 1
- 230000002401 inhibitory effect Effects 0.000 claims 1
- 230000005540 biological transmission Effects 0.000 description 6
- 230000002950 deficient Effects 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000002457 bidirectional effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/74—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for increasing reliability, e.g. using redundant or spare channels or apparatus
- H04B1/745—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission for increasing reliability, e.g. using redundant or spare channels or apparatus using by-passing or self-healing methods
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/42—Loop networks
- H04L12/437—Ring fault isolation or reconfiguration
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Small-Scale Networks (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A system is provided for automatically bypassing an inoperative data terminal so that other data terminals connected in series therewith will continue to receive data transmitted from a central data processor. The system in-cludes data terminal status indicators, a manual bypass capability, and a remote audio-visual alarm. The system is reponsive to the presence of output data at the output data terminals and includes switching means for bypassing data terminals when an absence of output data is sensed at the output data terminals.
A system is provided for automatically bypassing an inoperative data terminal so that other data terminals connected in series therewith will continue to receive data transmitted from a central data processor. The system in-cludes data terminal status indicators, a manual bypass capability, and a remote audio-visual alarm. The system is reponsive to the presence of output data at the output data terminals and includes switching means for bypassing data terminals when an absence of output data is sensed at the output data terminals.
Description
1 1 6406$
AUTOMATIC SHUNT DEVICE
This invention relates to data transmission sy-stems, and in particular to apparatus for shuntin~ data terminals.
A well-known technique for supplying data from a central processor to a plurality of data terminals in-cludes the series connection of said terminals, in a serial data loop, to output and input terminals of said central processor. The data received by the first data terminal in said series connection is sent ~n by said first terminal to the second series connected terminal and so on around the serial loop and back to the central data processor. With such a system, whenever one of the data terminals becomes inoperative, it interrupts operation of the entire data loop. Such interruptions often cause un-acceptable system downtime~ Several approaches have b~en employ~d for putting the remaining non-defective terminals back into an operative data loop.
One well-known technique is to employ a manual bypass switch for each data terminal ~hich has the capabil-ity of completely disconnecting the data terminal ~rom the data loop while at the same time providing a direct shunt ~hich re-establishes the series circuit and thus allows data to pass to the remaining terminals. t~ith such arran~e-ments the bypass switches for the various terminals are oftentimes mounted on a common switchboard to provide a central location for connecting or clisconnecting each of the terminals in the loop.
U.S. Patent No. 4,035,770 issued ~o Sarle on July 12, 1977, discloses a scanning system for locating and isolating a faulty terminal in a series connection of terminals. ~ith that syst~m, when the data loop is brok~n due -to a faulty terminal, a scanner circuit sequentially energizes bypass relays assoc;iated ~ith e~ch of the terminalc;. When the of~ending terrninal is reached in ~:he sequence, the data loop is reinstated arld said off~ndirg terminal :i5 located ancl elilninated f~o~ the loclp at the 1 ~ 6406~
same time. This arrangement requires that the data loop be out of commission during the time that the scanning is going on. For a large system this scanning time, which represents downtime, may be undesirably long.
` U.S. Patent No. 4,015~241 issued to Takezoe on March 29, 1977 shows in Figure 2 thereof a pair of bypass switches Ra and Rb which are used to shunt a comm~lnications terminal. Nothing in this patent appears to disclose what causes the switches to be actuated. The patent does dis-close an arrangement for checking the working condition of an addressed terminal and for transmitting information to said address terminal only when said terminal is in a working condition. The purpose of Takezoe is to increase the transmission efficiency of the system by eliminating the time that would be wasted during addressing of non-working terminals.
U.S. Patent No. 3,876,983 issued April 8, 1975 and its reissue Patent No. RE 28,~58 issued September 7, 1976 to Zafiropulo, et al. show a system for bypassing portions of a series loop with portions of a parallel loop.
It is an example of a very complex arrangement for locating and isolating faulty data terminals.
U.S. Patent No. 3,716,834 issued to Adams on February 13, 1973 discloses a data transmission system for locating and isolating circuit faults. Interrogation pulse signals are sent out from a central station to remote terminals, and reply signals are analyzed to determine the nature and location of the fault. This again is a complex arrangement requiring specialized central station in-terrogating and receiving apparatus.
U.S. Patent No. 3,601,806 issued to Heimbigner on August 24, 197] shows a complex bidirectional transmission system which includes the capability oF deactivating and bypassin~ certain remote terminals using a se~uential in--terrogation arrangemen-t accomplished by means of clock pulses transmitted from a master st;ation to the remote terrninals.
~ 1 64065 U.S. Patent No. 3,519,750 issued to Deresin, et.
al on July 7, 1970 discloses a complex communications system employing a second standby channel in combination with complex electronic switching gear for automatically re-establishing a broken transmission link between succes-sive stations.
None of the above-mentioned patents disclose or suggest the simple, instantaneously and automatically operating terminal shunting circuit of the instant inven-tion.
According to the present invention, there is provided an automatic shunt system for bypassing a data terminal having input terminals connected to an input data cable and output terminals for supplying output data,com-prising sensing means for sensing the presence or absence of output data at said output data terminals,and switching means responsive to an output signal of said sensing means for connecting said output data terminals to an output data cable only when data is present at said output data terminals, and for connecting said input data cable to said output data cable when data is absent at said output data terminals.
In order that the invention may be fully under-stood, it will now be described with reference to the accompanying drawings, in which:
Figure 1 shows an example of a known manual terminal bypass arrangement.
Figure 2 shows one example of an installation of the apparatus of the instant invention for automatic data terminal bypassing.
Figure 3 shows another convenient application of the apparatus of the invention.
Figure 4 shows yet another useful configuration employing the automatic shunt apparatus of this invention.
Figure 5 shows a circuit diagram of a preferred embodiment of an automatic shunt circuit for use with the instant invention.
1 ~ ~4065 Generally, in accordance with the invention, a central data processor and a plurality of data terminals are connected serially for transmission of data from the central processor through the data terminals and back to the data processor. Associated with each of the data ter-rninals in the serial data loop, is an automatic shunt circuit which senses output data leaving its associated data terminal and being transmitted onto the next terminal in the serial loop. When the data sensor in the shunt cir-cuit detects a cessation of data flowing out of its asso-ciated data terminal, the data sensor enables a relay coil driver. The coil driver then energizes a relay coil which in turn causes the switching of a two pole double throw relay. The relay is wired so that when energized it dis-connects the associated data terminal from the serial loop and at the same time re-establishes the serial loop by a direct through connection. When the non-operating data terminal is reactivated, the data sensor instantaneously disables the relay coil driver and the terminal is thus reinserted into the data loop. A manual switching means is also provided for energizing the relay coil so that the associated data terminal can be manually bypassed using this same apparatus. Colored light emitting diodes are used in the circuit to indicate the operational status of the data terminal, and a remote audio-visual alarm system is connected to be actuated when the cirucit has auto-matically bypassed its associated data terminal. As such, the circuit provides a simple and effective means for by-passing an inoperative terminal as well as providing for non-disruptive routine maintenance of the terminal.
Referring now to Figure 1, therein depicted is a known arrangement which provides for the manual bypassing of individual terminals which are connected in a serial data loop. The central data processor (2) transmits data out along data cable (4) through manual bypass switch (BP4) and on to data terrninal lT4). Once the data is received by data terminal (T4), it is then transmitted on in the ~ ~ 64065 direction shown by the arrows through bypass switch (BP4) and bypass switch (BP3) to data terminal (T3). The data continues to work its way around the serial loop until finally returning to the central data processor (2).
If any one of the data terminals Tl - T4 becomes inoperative, it disables the entire data loop. Once the offending terminal has been located, its associated manual bypass switch may be operated to isolate that terminal and re-establish the data loop. The manual bypass switches BPl - BP4 are three pole double throw switches connected in a conventional manner to accomplish the desired isola-tion and bypass function. These bypass switches are normal-ly mounted on a common manual bypass switchboard. With this arrangement a single defective data terminal will cause the entire data loop to go out of order until the defective terminal's associated bypass switch is manually operated, thus resulting in an undesirably long sys-tem downtime.
Figure 2 shows a modification of the above-described prior art arrangement wherein the automatic shunt circuits Sl - S4 (as depicted in detail in Figure 5) accor-ding to the instant invention are interposed between the manual bypass switches BPl - BP4 and the data terminals Tl - T4. With the arrangmenet of Figure 2, the automatic shunts Sl - S4 are installed at the data terminal loca-tions.
Figure 3 depicts an arrangement wherein the auto-matic shunt circuits Sl - S4 of Figure 5 according to the instant invention are mounted at the location of the manual bypass switchboard. This arrangement includes the desirable feature of additionally providing for the automatic moni-toring by the automatic shunt circuits Sl - S4 of the con-dition of the data cables connected between the terminals Tl - T4 and the switchboard (6).
Another useful arrangement employing the auto-matic shunt circuit of Figure 5 according to this invention is shown in Figure 4. With this configuration the manual bypass switchboard (6) of Figures 1, 2 and 3, is eliminated altogether. The automatic shunts Sl - S4 are the only means g 1 64065 of bypassing their associated data terminals Tl - T4. This is a practical arrangement, since according to the inven-tion the automatic shunts Sl - S4 are operable both in an automatic and a manual mode. Thus there is no real need for additional manual bypass switches.
A preferred embodiment for an automatic shunt circuit according to the instant invention is shown within the dotted lines of Figure 5. The circuit is shown as an automatic bypass for data terminal T3 as depicted in Figures 2, 3 and 4.
SWl is a double pole double throw relay which is connected as shown so that when its associated relay coil (8) is unenergized, the relay pole contacts Pl and P2 are connected to the normally closed terminals NCl and NC2. Thus, when the relay coil (8) remains unenergized, the data received from data terminal T4 is sent directly through to data terminal T3 and then transmitted from data terminal T3 through relay SW1 and on to data terminal T2.
The data flow out of data terminal T3 is moni-tored by data sensor (10). Such sensors are well-known in the digital circuit art and are commonly employed to determine the absence or presence of digital data at a particular point in a circuit. When the sensor (10) detects the absence of digital data at the data out terminals of data terminal T3, the sensor generates a warning signal SX. This signal is applied to time delay circuit (12).
If the data flow from the DATA OUT terminals of data ter-minal T3 is interrupted for more than a predetermined time, as is programmed into time delay circuit (12), it in turn activates the relay coil driver (14). When activated, this relay coil driver presents a low impedance between ter-minal (16) of resistor Rl and system ground terminal (18).
Thus, enabling current flow from the power supply (20) through the relay coil (8) and its current limiting resis-tor ~1.
1 1 6~065 When energized, the relay coil (8) causes the relay SWl to disconnect poles Pl and P2 from terminals NCl and NC2, respectively, and in turn connect poles Pl and P2 to terminals NOl and N02, respectively. As a result, the data terminal T3 is disconnected from the data loop and is replaced with a direct through connection. The relay SWl will stay in this condition until digital data again is produced at the DATA OUT terminals of data terminal T3.
When relay coil (8) is energized, the output voltage Vs of power supply (20) appears across the series connection of the red light emitting diode (22) and its associated current limiting diode (24) and resistor R2.
Thus, a red visual warning signal is generated when data terminal T3 is disconnected and bypassed.
When data terminal T3 is in proper working con-dition, and data is being generated at its DATA OUT ter-minals, no warning signal SX is generated. With this situa-tion the relay coil driver (14) presents a very high impe-dance between ground terminal (18) and terminal (16). Thus, the relay coil (8) is de-energized except for a very small current which flows through it and on through the series connection of current limiting diode (26), resistor R3, and green light emitting diode (28). Thus, when data ter-minal T3 is operational, a green visual signal is gene-rated.
Switch SW2 is a single pole double throw switch which provides the circuit with both a manual and an auto-matic mode. When the switch SW2 is in the AUTOMATIC posi-tion, a remote audio-visual alarm is connected across the series connection of the relay coil (8) and its current limiting resistor Rl. Thus, when the relay coil (8) is energized, the remote alarm (30) is also activated, and it remains activated until such time as data terminal T3 again generates output data or until switch SW2 is turned to the MANUAL position.
t 1 64065 When switch S2 is put in the MANUAL position, t,he relay coil (8) will be energized regardless of the operational status of data terminal T3. Thus, switch SW2 can be used to implement the bypassing of the data terminal for reasons other than a malfunction of the terminal --such as, for example, the performance of routine mainte-nance on the terminal equipment. The whole shunt circuit S3 is energized by power supply (20) which in turn is con-nected to a standard 120 volt alternating current line.
It is to be understood that numerous modifica-tions apparent to these skilled in the art could be made to the above-described preferred embodiment without depar-ting from the spirit and scope of the invention as recited in the following claims.
AUTOMATIC SHUNT DEVICE
This invention relates to data transmission sy-stems, and in particular to apparatus for shuntin~ data terminals.
A well-known technique for supplying data from a central processor to a plurality of data terminals in-cludes the series connection of said terminals, in a serial data loop, to output and input terminals of said central processor. The data received by the first data terminal in said series connection is sent ~n by said first terminal to the second series connected terminal and so on around the serial loop and back to the central data processor. With such a system, whenever one of the data terminals becomes inoperative, it interrupts operation of the entire data loop. Such interruptions often cause un-acceptable system downtime~ Several approaches have b~en employ~d for putting the remaining non-defective terminals back into an operative data loop.
One well-known technique is to employ a manual bypass switch for each data terminal ~hich has the capabil-ity of completely disconnecting the data terminal ~rom the data loop while at the same time providing a direct shunt ~hich re-establishes the series circuit and thus allows data to pass to the remaining terminals. t~ith such arran~e-ments the bypass switches for the various terminals are oftentimes mounted on a common switchboard to provide a central location for connecting or clisconnecting each of the terminals in the loop.
U.S. Patent No. 4,035,770 issued ~o Sarle on July 12, 1977, discloses a scanning system for locating and isolating a faulty terminal in a series connection of terminals. ~ith that syst~m, when the data loop is brok~n due -to a faulty terminal, a scanner circuit sequentially energizes bypass relays assoc;iated ~ith e~ch of the terminalc;. When the of~ending terrninal is reached in ~:he sequence, the data loop is reinstated arld said off~ndirg terminal :i5 located ancl elilninated f~o~ the loclp at the 1 ~ 6406~
same time. This arrangement requires that the data loop be out of commission during the time that the scanning is going on. For a large system this scanning time, which represents downtime, may be undesirably long.
` U.S. Patent No. 4,015~241 issued to Takezoe on March 29, 1977 shows in Figure 2 thereof a pair of bypass switches Ra and Rb which are used to shunt a comm~lnications terminal. Nothing in this patent appears to disclose what causes the switches to be actuated. The patent does dis-close an arrangement for checking the working condition of an addressed terminal and for transmitting information to said address terminal only when said terminal is in a working condition. The purpose of Takezoe is to increase the transmission efficiency of the system by eliminating the time that would be wasted during addressing of non-working terminals.
U.S. Patent No. 3,876,983 issued April 8, 1975 and its reissue Patent No. RE 28,~58 issued September 7, 1976 to Zafiropulo, et al. show a system for bypassing portions of a series loop with portions of a parallel loop.
It is an example of a very complex arrangement for locating and isolating faulty data terminals.
U.S. Patent No. 3,716,834 issued to Adams on February 13, 1973 discloses a data transmission system for locating and isolating circuit faults. Interrogation pulse signals are sent out from a central station to remote terminals, and reply signals are analyzed to determine the nature and location of the fault. This again is a complex arrangement requiring specialized central station in-terrogating and receiving apparatus.
U.S. Patent No. 3,601,806 issued to Heimbigner on August 24, 197] shows a complex bidirectional transmission system which includes the capability oF deactivating and bypassin~ certain remote terminals using a se~uential in--terrogation arrangemen-t accomplished by means of clock pulses transmitted from a master st;ation to the remote terrninals.
~ 1 64065 U.S. Patent No. 3,519,750 issued to Deresin, et.
al on July 7, 1970 discloses a complex communications system employing a second standby channel in combination with complex electronic switching gear for automatically re-establishing a broken transmission link between succes-sive stations.
None of the above-mentioned patents disclose or suggest the simple, instantaneously and automatically operating terminal shunting circuit of the instant inven-tion.
According to the present invention, there is provided an automatic shunt system for bypassing a data terminal having input terminals connected to an input data cable and output terminals for supplying output data,com-prising sensing means for sensing the presence or absence of output data at said output data terminals,and switching means responsive to an output signal of said sensing means for connecting said output data terminals to an output data cable only when data is present at said output data terminals, and for connecting said input data cable to said output data cable when data is absent at said output data terminals.
In order that the invention may be fully under-stood, it will now be described with reference to the accompanying drawings, in which:
Figure 1 shows an example of a known manual terminal bypass arrangement.
Figure 2 shows one example of an installation of the apparatus of the instant invention for automatic data terminal bypassing.
Figure 3 shows another convenient application of the apparatus of the invention.
Figure 4 shows yet another useful configuration employing the automatic shunt apparatus of this invention.
Figure 5 shows a circuit diagram of a preferred embodiment of an automatic shunt circuit for use with the instant invention.
1 ~ ~4065 Generally, in accordance with the invention, a central data processor and a plurality of data terminals are connected serially for transmission of data from the central processor through the data terminals and back to the data processor. Associated with each of the data ter-rninals in the serial data loop, is an automatic shunt circuit which senses output data leaving its associated data terminal and being transmitted onto the next terminal in the serial loop. When the data sensor in the shunt cir-cuit detects a cessation of data flowing out of its asso-ciated data terminal, the data sensor enables a relay coil driver. The coil driver then energizes a relay coil which in turn causes the switching of a two pole double throw relay. The relay is wired so that when energized it dis-connects the associated data terminal from the serial loop and at the same time re-establishes the serial loop by a direct through connection. When the non-operating data terminal is reactivated, the data sensor instantaneously disables the relay coil driver and the terminal is thus reinserted into the data loop. A manual switching means is also provided for energizing the relay coil so that the associated data terminal can be manually bypassed using this same apparatus. Colored light emitting diodes are used in the circuit to indicate the operational status of the data terminal, and a remote audio-visual alarm system is connected to be actuated when the cirucit has auto-matically bypassed its associated data terminal. As such, the circuit provides a simple and effective means for by-passing an inoperative terminal as well as providing for non-disruptive routine maintenance of the terminal.
Referring now to Figure 1, therein depicted is a known arrangement which provides for the manual bypassing of individual terminals which are connected in a serial data loop. The central data processor (2) transmits data out along data cable (4) through manual bypass switch (BP4) and on to data terrninal lT4). Once the data is received by data terminal (T4), it is then transmitted on in the ~ ~ 64065 direction shown by the arrows through bypass switch (BP4) and bypass switch (BP3) to data terminal (T3). The data continues to work its way around the serial loop until finally returning to the central data processor (2).
If any one of the data terminals Tl - T4 becomes inoperative, it disables the entire data loop. Once the offending terminal has been located, its associated manual bypass switch may be operated to isolate that terminal and re-establish the data loop. The manual bypass switches BPl - BP4 are three pole double throw switches connected in a conventional manner to accomplish the desired isola-tion and bypass function. These bypass switches are normal-ly mounted on a common manual bypass switchboard. With this arrangement a single defective data terminal will cause the entire data loop to go out of order until the defective terminal's associated bypass switch is manually operated, thus resulting in an undesirably long sys-tem downtime.
Figure 2 shows a modification of the above-described prior art arrangement wherein the automatic shunt circuits Sl - S4 (as depicted in detail in Figure 5) accor-ding to the instant invention are interposed between the manual bypass switches BPl - BP4 and the data terminals Tl - T4. With the arrangmenet of Figure 2, the automatic shunts Sl - S4 are installed at the data terminal loca-tions.
Figure 3 depicts an arrangement wherein the auto-matic shunt circuits Sl - S4 of Figure 5 according to the instant invention are mounted at the location of the manual bypass switchboard. This arrangement includes the desirable feature of additionally providing for the automatic moni-toring by the automatic shunt circuits Sl - S4 of the con-dition of the data cables connected between the terminals Tl - T4 and the switchboard (6).
Another useful arrangement employing the auto-matic shunt circuit of Figure 5 according to this invention is shown in Figure 4. With this configuration the manual bypass switchboard (6) of Figures 1, 2 and 3, is eliminated altogether. The automatic shunts Sl - S4 are the only means g 1 64065 of bypassing their associated data terminals Tl - T4. This is a practical arrangement, since according to the inven-tion the automatic shunts Sl - S4 are operable both in an automatic and a manual mode. Thus there is no real need for additional manual bypass switches.
A preferred embodiment for an automatic shunt circuit according to the instant invention is shown within the dotted lines of Figure 5. The circuit is shown as an automatic bypass for data terminal T3 as depicted in Figures 2, 3 and 4.
SWl is a double pole double throw relay which is connected as shown so that when its associated relay coil (8) is unenergized, the relay pole contacts Pl and P2 are connected to the normally closed terminals NCl and NC2. Thus, when the relay coil (8) remains unenergized, the data received from data terminal T4 is sent directly through to data terminal T3 and then transmitted from data terminal T3 through relay SW1 and on to data terminal T2.
The data flow out of data terminal T3 is moni-tored by data sensor (10). Such sensors are well-known in the digital circuit art and are commonly employed to determine the absence or presence of digital data at a particular point in a circuit. When the sensor (10) detects the absence of digital data at the data out terminals of data terminal T3, the sensor generates a warning signal SX. This signal is applied to time delay circuit (12).
If the data flow from the DATA OUT terminals of data ter-minal T3 is interrupted for more than a predetermined time, as is programmed into time delay circuit (12), it in turn activates the relay coil driver (14). When activated, this relay coil driver presents a low impedance between ter-minal (16) of resistor Rl and system ground terminal (18).
Thus, enabling current flow from the power supply (20) through the relay coil (8) and its current limiting resis-tor ~1.
1 1 6~065 When energized, the relay coil (8) causes the relay SWl to disconnect poles Pl and P2 from terminals NCl and NC2, respectively, and in turn connect poles Pl and P2 to terminals NOl and N02, respectively. As a result, the data terminal T3 is disconnected from the data loop and is replaced with a direct through connection. The relay SWl will stay in this condition until digital data again is produced at the DATA OUT terminals of data terminal T3.
When relay coil (8) is energized, the output voltage Vs of power supply (20) appears across the series connection of the red light emitting diode (22) and its associated current limiting diode (24) and resistor R2.
Thus, a red visual warning signal is generated when data terminal T3 is disconnected and bypassed.
When data terminal T3 is in proper working con-dition, and data is being generated at its DATA OUT ter-minals, no warning signal SX is generated. With this situa-tion the relay coil driver (14) presents a very high impe-dance between ground terminal (18) and terminal (16). Thus, the relay coil (8) is de-energized except for a very small current which flows through it and on through the series connection of current limiting diode (26), resistor R3, and green light emitting diode (28). Thus, when data ter-minal T3 is operational, a green visual signal is gene-rated.
Switch SW2 is a single pole double throw switch which provides the circuit with both a manual and an auto-matic mode. When the switch SW2 is in the AUTOMATIC posi-tion, a remote audio-visual alarm is connected across the series connection of the relay coil (8) and its current limiting resistor Rl. Thus, when the relay coil (8) is energized, the remote alarm (30) is also activated, and it remains activated until such time as data terminal T3 again generates output data or until switch SW2 is turned to the MANUAL position.
t 1 64065 When switch S2 is put in the MANUAL position, t,he relay coil (8) will be energized regardless of the operational status of data terminal T3. Thus, switch SW2 can be used to implement the bypassing of the data terminal for reasons other than a malfunction of the terminal --such as, for example, the performance of routine mainte-nance on the terminal equipment. The whole shunt circuit S3 is energized by power supply (20) which in turn is con-nected to a standard 120 volt alternating current line.
It is to be understood that numerous modifica-tions apparent to these skilled in the art could be made to the above-described preferred embodiment without depar-ting from the spirit and scope of the invention as recited in the following claims.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An automatic shunt system for bypassing a data terminal having input terminals connected to an input data cable and output terminals for supplying output data, com-prising sensing means for sensing the presence or absence of output data at said output data terminals, and switching means responsive to an output signal of said sensing means for connecting said output data terminals to an output data cable only when data is present at said output data ter-minals, and for connecting said input data cable to said output data cable when data is absent at said output data terminals.
2. A system according to Claim 1, further com-prising delay means for inhibiting the transfer of said sensing means output signal to said switching means for a predetermined time period.
3. A system according to Claim 1, further com-prising visual display means for indicating which of said connections has been made by said switching means.
4. A system according to Claim 3, wherein said visual display means comprise light emitting diodes.
5. A system according to Claim 1, 2, or 3, further comprising audio and visual alarm means responsive to said sensing means for indicating when said input cable has been connected to said output cable by said switching means.
6. A system according to Claim 1, 2, or 3, further comprising switch means for manually activating said switching means.
7. A system according to Claim 1, 2, or 3, wherein said switching means comprises a multiple pole, double throw relay and a relay coil driver connected thereto.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/944,804 US4245343A (en) | 1978-09-22 | 1978-09-22 | Automatic shunt device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1164065A true CA1164065A (en) | 1984-03-20 |
Family
ID=25482101
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363711A Expired CA1164065A (en) | 1978-09-22 | 1980-10-31 | Automatic shunt device |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4245343A (en) |
| JP (1) | JPS5789353A (en) |
| CA (1) | CA1164065A (en) |
| DE (1) | DE3044203A1 (en) |
| GB (1) | GB2089176A (en) |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4374436A (en) * | 1980-10-17 | 1983-02-15 | Paradyne Corporation | System for the monitoring and restoration of series terminals in a looped communication system |
| US4393492A (en) * | 1981-02-17 | 1983-07-12 | Reliance Electric Co. | Digital subscriber carrier system including drop terminals and bypass and loopback means and alarm indication means |
| JPH0710068B2 (en) * | 1983-05-09 | 1995-02-01 | キヤノン株式会社 | Transmission control device |
| JPS6038950A (en) * | 1983-08-11 | 1985-02-28 | Sumitomo Electric Ind Ltd | Transmission path control method |
| IE832561L (en) * | 1983-11-02 | 1985-05-02 | Nat Microelectronics Applic Ct | Apparatus for handling data |
| US4639891A (en) * | 1983-11-14 | 1987-01-27 | Digital Equipment Corporation | Signals path control circuitry for a data terminal |
| JPS60107936A (en) * | 1983-11-16 | 1985-06-13 | Fujitsu Ltd | Auxiliary signal inserting circuit |
| GB2168574B (en) * | 1984-12-15 | 1988-05-05 | Stc Plc | Transmission system |
| US4706271A (en) * | 1985-05-03 | 1987-11-10 | Communications Technology Corporation | Communication lines with terminate and leave capability-DC alarm bridge |
| CA1252168A (en) * | 1985-07-24 | 1989-04-04 | Kenneth A. Bobey | Communications network |
| US4910791A (en) * | 1985-12-26 | 1990-03-20 | Am Communications, Inc. | Monitoring and control of data communications |
| US4763329A (en) * | 1986-02-10 | 1988-08-09 | Techlan, Inc. | Modular data routing system |
| GB8612454D0 (en) * | 1986-05-22 | 1986-07-02 | Inmos Ltd | Redundancy scheme for multi-stage apparatus |
| US4939730A (en) * | 1988-10-11 | 1990-07-03 | Gilbarco Inc. | Auto isolation circuit for malfunctioning current loop |
| CA2058654C (en) * | 1991-12-31 | 1998-12-29 | Thomas Gray | Data transport for internal messaging |
| US5651000A (en) * | 1995-04-27 | 1997-07-22 | International Business Machines Corporation | Method and systems for determining the nearest downstream reconfiguration unit in a dual ring communication system |
| GB2318262B (en) * | 1996-10-08 | 2000-11-08 | Ibm | Bypass circuit for data processing system |
| US6327242B1 (en) * | 1998-03-17 | 2001-12-04 | Infolibria, Inc. | Message redirector with cut-through switch for highly reliable and efficient network traffic processor deployment |
| US6535509B2 (en) | 1998-09-28 | 2003-03-18 | Infolibria, Inc. | Tagging for demultiplexing in a network traffic server |
| US7149222B2 (en) * | 1999-12-21 | 2006-12-12 | Converged Access, Inc. | Integrated access point network device |
| US20080310298A1 (en) * | 2007-06-15 | 2008-12-18 | Geir Andre Motzfeldt Drange | Providing Bypass Switches to Bypass Faulty Nodes |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1351443A (en) * | 1961-11-10 | 1964-05-06 | Ibm | Message communication device |
| SE308038B (en) * | 1968-04-18 | 1969-01-27 | Ericsson Telefon Ab L M | |
| US3599179A (en) * | 1969-05-28 | 1971-08-10 | Westinghouse Electric Corp | Fault detection and isolation in computer input-output devices |
| GB1229149A (en) * | 1969-07-28 | 1971-04-21 | ||
| US3716834A (en) * | 1971-10-07 | 1973-02-13 | H Adams | Data transmission system with immunity to circuit faults |
| USRE28958E (en) | 1973-05-30 | 1976-09-07 | International Business Machines Corporation | Synchronous disconnection and rearrangement |
| US3879710A (en) * | 1974-03-01 | 1975-04-22 | Rca Corp | Data processor for a loop data communications system |
| US4075440A (en) * | 1976-07-26 | 1978-02-21 | Rockwell International Corporation | Automatic communication system reconfiguration apparatus |
-
1978
- 1978-09-22 US US05/944,804 patent/US4245343A/en not_active Expired - Lifetime
-
1980
- 1980-10-31 CA CA000363711A patent/CA1164065A/en not_active Expired
- 1980-11-13 GB GB8036518A patent/GB2089176A/en not_active Withdrawn
- 1980-11-21 JP JP55165211A patent/JPS5789353A/en active Pending
- 1980-11-24 DE DE19803044203 patent/DE3044203A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| US4245343A (en) | 1981-01-13 |
| DE3044203A1 (en) | 1982-06-24 |
| JPS5789353A (en) | 1982-06-03 |
| GB2089176A (en) | 1982-06-16 |
| US4245343B1 (en) | 1988-07-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |